


Vibrational Motion

by Writer_Geekgirl



Series: Castiel and Dean: A Roommate Love Story [24]
Category: Supernatural
Genre: Alternate Universe - Roommates/Housemates, Castiel and Dean Winchester are Roommates, Fluff and Humor, M/M, Professor Castiel (Supernatural), Yoga Instructor Castiel (Supernatural)
Language: English
Status: Completed
Published: 2019-04-25
Updated: 2019-04-25
Packaged: 2020-01-31 13:42:53
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 808
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18592411
Author URL: https://archiveofourown.org/users/Writer_Geekgirl/pseuds/Writer_Geekgirl
Summary: Castiel provides a physics lesson on vibrations to Dean while Dean's at work.This work is part of a 30 Day OTP Challenge prompt series. The stories are inspired by a different phrase each day but the short vignettes will all tie in together and weave a larger story. Each story will be standalone (for the most part).The prompt for the day is: Something NSFW





	Vibrational Motion

**Author's Note:**

> My apologies for anything I got wrong on vibrational physics. It's been a long time since college :).

Dean stepped out of his bedroom to head to work. Castiel was stretching in the living room in shorts and a muscle shirt. Dean whistled appreciatively. Castiel flashed him a smile before approaching Dean to adjust his tie.

Dean smiled, "Man, I love the way you dress for work. Changing careers for you was a good thing for me, I'm sure you are much hotter as a yoga instructor than a stodgy old professor."

Castiel arched an eyebrow, "You don't think I was sexy when I was a TA in college?"

"Cas, you could wear a burlap sack and be sexy."

Castiel snorted, "I'll have you know that sweet young coeds appeared at my office door every few minutes despite their disinterest in physics. Little did they know they were barking up the wrong tree."

"I'm sure you were sexy, Cas. I just meant… What you get to wear to work is hot. I can't imagine you any hotter as a college professor."

Castiel bit his bottom lip for a second before looking speculatively at Dean. "You eating lunch at your desk, Dean?"

"Yeah, I got to finish a drawing for Dick. I hate that man," Dean grumbled.

"I'll call you for a few minutes at lunchtime to cheer you up," Castiel winked.

Dean kissed Castiel gently before heading out the door. 

He was at his desk when his phone when FaceTime lit up with an incoming call from Castiel at noon. Dean walked to one of the small conference rooms and answered the call. He was startled when Castiel appeared dressed in a tweed jacket, a bow tie, and horn-rimmed glasses. He had a ruler in one hand, tapping it on his other hand.

"In today's physics lesson, class, we are going to talk about vibrational motion," Castiel said in a husky voice. " Vibrational motion occurs when an object moves across the same path over a period of time. Imagine a vibration as a spring mounted on a board that is locked and loaded and compressed. You have your hand pressed down on that…" Castiel paused and licked his lips, "mounted spring. You then slowly, ever so slowly, release that spring. The spring will rise and then fall over and over and over again until damping forces are produced by processes that dissipate the energy stored in the oscillation." Castiel removed his bow tie. "Can't you just imagine how that spring would rise and fall, Dean? Over and over again. "His voice lowered again.

Dean felt a tightening in his pants, "Um, Cas."

Castiel dropped the bowtie. "Now as the spring rises and falls the vibration is considered periodic motion. You can graph the motion of that mass… that mass that is moving up and down over and over… on a graph that compares motion to time." Castiel shrugged off his coat. Only a white button-up shirt remained.

Dean groaned, "Cas… I'm not sure this is the time or the place."

"Quiet, Mr. Winchester. No speaking in class," Castiel responded in a husky voice. Then he smiled slightly, "Unless you want the class to be dismissed, Dean. I can dismiss class if you'd like. I'll stop this whenever you want."

Dean just bit his lip and stared at his phone. 

Castiel continued, "If you look at the graph, the oscillation goes up and down with motion on the x-axis and time on the y-axis. The rhythmic and periodic forces form a sine wave on the graph." Castiel unbuttoned his shirt slowly and tossed it aside. Dean couldn't breathe as he stared at Castiel's tanned chest and torso. Castiel nonchalantly pushed his glasses up his nose. "The sine wave illustrates that damping occurs with the mass-spring system. Some energy is being dissipated over the course of time. The vibration starts to slow over time until all that energy has gone…" He dropped his voice an octave, "and the mass returns to a resting state until such a time that you compress that spring again. The vibrational force has been sated, finished as the energy dissipates." Castiel licked his lips again.

"Shit, Cas, that is so friggin' hot," Dean sputtered.

"Do you like compressing a mounted spring to illustrate vibrational motion, Dean?"

A sharp voice called through the office, "Winchester, where are you?"

Dean grumbled, "Dammit, it's Dick."

Castiel raised an eyebrow, "Yes, yes, it is."

Dean called out nervously, "Coming, sir."

"Are you? Are you really, Dean?" Castiel smirked.

"Cas, you are an ass."

"I never claimed not to be. Have a nice day at work, honey." Castiel smiled as he ended the call.

Dean put his phone in a pocket He took off slid off his suit jacket and folded it over his arm to hide the front of his pants as he went off in search of Dick. It was going to be a long afternoon.


End file.
